A teacher was among the 17 people burned to death in eastern Pakistan when a minibus taking children to school suddenly caught fire.
Police had earlier said that all 17 who died in the Saturday morning blaze in Gujrat, about 120 miles north-west of Islamabad, were children aged between 6 and 12.
Officer Ijaz Ahmad said a short-circuit next to a leaking gasoline tank started the blaze. Police earlier blamed an exploding natural gas cylinder. The bus was powered with both types of fuel.
He said an unspecified number of children were injured, some listed in critical condition.
The accident comes after a pair of suspected militant attacks killed nine people in two different areas of north-west Pakistan on Friday.
In the deadlier of the two attacks, suspected militants armed with heavy weapons attacked a police convoy in Mattani, 12 miles south of the main north-west city of Peshawar, killing six policemen and wounding seven others, said senior police officer Shafiullah Khan.
In the second attack on Friday, a suicide bomber walked up to a vehicle owned by an Afghan religious leader in Peshawar and set off his explosives, killing three people, said police officer Riaz Ali Shah.
The leader, Haji Hayatullah, was not harmed in the attack because he was in a nearby mosque attending Friday prayers. Hayatullah's driver and guard were killed, said Shah. A passer-by was also killed and two others were wounded, said Peshawar police chief Liaquat Ali Khan.
There are more than one million refugees in Pakistan from neighbouring Afghanistan. No one has claimed responsibility for the attacks.